1. Technical Field
The present invention relates to an optical filter, an optical filter module, and a photometric analyzer.
2. Related Art
In related art, an optical filter that extracts a light having a specific wavelength from light having plural wavelengths has been known. As an example of the optical filter, there is a tunable interference filter, for example.
The tunable interference filter is an optical filter in which optical films formed on substrates are oppositely provided and a gap between the optical films is changed by an external force to transmit a light having a wavelength in response to the gap dimension (see Patent Document 1 (JP-A-11-142752)).
However, in the tunable interference filter having the above described configuration, as the gap between optical films is made smaller by an external force, the substrates are deformed in the parts in which the optical films are formed and flatness within the optical film surfaces may not be ensured. Accordingly, there are problems that it is impossible to ensure a uniform gap within the surfaces of the opposed optical films and spectroscopic accuracy of the optical filter is reduced.